Diffusion, Osmosis & Active Transport

• Diffusion is the movement of particles from an area of high concentration to low concentration.
• Osmosis is the movement of water across a semi-permeable membrane from a region of higher water concentration to a region of lower water concentration
• Factors affecting diffusion:

  • Surface area
  • Temperature
  • concentration gradient
• Osmosis practical:

  1. Weight & place cylinders from same vegetable in sugar solutions varying concentrations
  2. After set time, remove excess water and reweigh, calculate percentage change in mass
  3. (Final mass - initial mass) / initial mass x 100
• Active transport is the movement of particles from an area of low concentration to an area of high concentration.
• Active transport requires energy, whereas diffusion doesn't (Passive)
• Define Diffusion?


  the movement of particles from an area of high concentration to low concentration